According to conventional technology for identifying the motor constants of a permanent magnet motor by a driving device itself, an electric current passing through the motor and a voltage applied to the motor are controlled so as to identify the motor constants, in order to identify a counter-electromotive voltage constant of the motor. (Refer to, for example, patent document 1).
Also there is technology in which, as with above, an electric current passing through a motor and a voltage applied to the motor are controlled so as to identify motor constants, to identify a counter-electromotive voltage constant of the motor. (Refer to, for example, patent document 2).
Also there is technology in which an applied voltage is interrupted during the rotation of a motor, and a terminal voltage and a speed are detected at that time to calculate a counter-electromotive voltage constant. (Refer to, for example, patent document 3).
Also there is technology in which a predetermined input current is fed through an axis in an arbitrary direction, and the magnetic flux φ of a magnet in a permanent magnet motor is detected during its rotation on a coordinate axis in a direction orthogonal to the arbitrary direction, on which the current became zero. (Refer to, for example, patent document 4).
Also there is a technology in which a calculation coefficient of a magnetic flux calculator of a permanent magnet motor is adjusted in accordance with an electric current of a dq-axis component, in order to identify flux interlinkage. (Refer to, for example, patent document 5).
Also there is a technology in which the flux interlinkage of a permanent magnet motor is estimated from a torque command current value and a fed-back torque current detection value, and the torque command current value is output on the basis of the estimated flux interlinkage. (Refer to, for example, patent document 6).
Also there is a technology in which the inductances of a permanent magnet motor in a d-axis and a q-axis are measured by the static coordinate transformation of a current which is obtained by the application of three types of pulses. (Refer to, for example, patent document 7).
Also there is a technology relating to an energy saving service which offers an energy-saving effect with reduced initial investment due to the installation of an inverter. (Refer to, for example, patent documents 8 and 9).
[Patent document 1] Japanese Patent Laid-Open Publication No. 2000-341999
[Patent document 2] Japanese Patent Laid-Open Publication No. Hei 9-191698
[Patent document 3] Japanese Patent Laid-Open Publication No. 2000-245191
[Patent document 4] Japanese Patent Laid-Open Publication No. 2000-312498
[Patent document 5] Japanese Patent Laid-Open Publication No. Hei 9-182499
[Patent document 6] Japanese Patent Laid-Open Publication No. Hei 10-229700
[Patent document 7] Japanese Patent Laid-Open Publication No. 2001-69783
[Patent document 8] Japanese Patent Laid-Open Publication No. 2001-155083
[Patent document 9] Japanese Patent Laid-Open Publication No. 2002-327947
The technology disclosed in the patent document 1 adopts a position sensor-less method, by which the position of a rotor of a synchronous motor is not detected. Thus, a control block also estimates the speed and position at the same time.
To estimate the speed and the position, motor constants are necessary. However, the motor constants are identified after an induced voltage has been estimated from an estimated value and a detection value of a current in a γδ axis for the identification. When the control block is structured in such a manner, an error in the identification of the motor constants causes an error in the estimation of the speed and position. Furthermore, the error in the estimation of the rotor position causes an error in a section for converting three-phase current into the current in the γδ axis. Therefore, since control was made viable by estimating estimation, it was necessary to make an error added up with respect to all of estimation as small as possible, and hence high-performance control was difficult.
Furthermore, the current in the γδ axis was controlled to identify the constants, so that the voltage was applied for identification. The motor was used with low efficiency because any optimal voltage, by which the motor was at a maximum efficiency operating point, was not applied. The technology disclosed in the patent document 1 pursued control performance such as response speed and stability rather than the efficiency of the motor. Therefore, the technology disclosed in the patent document 1 could not satisfy optimization in the efficiency of the motor, energy saving, and the like.
The patent document 2 discloses the similar technology. A control block for identifying and estimating motor constants, however, is contained in a control block for estimating a position. This is also the technology for pursuing control performance, and cannot satisfy optimization in the efficiency of the motor, energy saving, and the like.
Furthermore, in the technology disclosed in the patent document 3, the applied voltage is interrupted during the rotation of the motor. By detecting the terminal voltage and speed at that time, a counter-electromotive voltage constant is calculated. In the technology disclosed in the patent document 3, since the applied voltage is interrupted even temporarily, the speed of the motor slows down. Thus, there are cases where the applied voltage cannot be interrupted according to a load connected to the motor. When the inertial force of the load is small, high detection speed response is also necessary to quickly detect the terminal voltage and speed of the motor after the interruption of the applied voltage. The detection of the speed in such a state requires extremely high accuracy and high cost.
If the interruption of the applied voltage is instantaneously cleared, there are cases where the speed of the motor slows down to a stop state or nearly the stop state, and a restart becomes necessary. In the case of sensor-less drive, it cannot be assured that the restart is certainly carried out one hundred percent. Thus, there is a possibility that the motor stops even temporarily to identify the counter-electromotive voltage constant.
Furthermore, the patent document 4 also discloses the technology about a method for identifying motor constants of the permanent magnet synchronous motor. A method for detecting the magnetic flux φ of the permanent magnet during its rotation is disclosed. The motor, however, has the structure of sensor drive using a position sensor, instead of position sensor-less drive, so that it is extremely difficult to apply the technology disclosed in the patent document 4 to the sensor-less drive from the viewpoint of cost and technology.
The patent documents 5 and 6 disclose the technology for identifying motor constants. The technology can detect the motor constants with high precision with the use of a position sensor, as with above, but cannot be applied to position sensor-less drive.
Furthermore, the patent document 7 discloses the technology for measuring the inductances by applying the pulses. However, it is known that the motor is an LR load, and it is also known that a resistance component (R) of an LR circuit is ignorable by applying the pulses for minute time. According to the technology disclosed in the patent document 7, an electric current, which is obtained by applying the three types of pulses, that is, u+, v−, and w−, and u−, v+, and w−, and u−, v−, and w+ of a switching element, is subjected to the static coordinate transformation, to measure the inductances.
Assuming that the pulses are applied for the minute time in such a manner, however, it is described that the minute time is sufficiently shorter than a time constant L/R of the permanent magnet motor. There is a contradiction that pulse time for measuring the unknown motor constants is sufficiently shorter than the time constant L/R of the motor constants.
Furthermore, when the pulse time is too short, sufficient electric current does not flow, and residual magnetic flux due to the application of the pulses causes an offset in the electric current. Thus, there is a problem that the inductances cannot be measured with precision. To solve this problem, it is necessary to elongate the minute time of applying the pulses. The minute time, however, has to be sufficiently shorter than the time constant L/R of the motor constant. Thus, this method is effective when a value of an inductance component has been already known to a certain degree, but is difficult to use when the value of the inductance component has been unknown.
The patent document 7 also discloses the technology for calculating a counter-electromotive voltage constant. According to the technology in this publication, an electromotive coefficient is adjusted so as to adjust an error in speed due to electromotive force which has been estimated during existing sensor-less drive. Thus, the technology is available only in sensor-less control for estimating the electromotive force.
Furthermore, the patent documents 8 and 9 disclose the services which provide a user with the merit of an electric power saving effect by capacity control by the inverter, if the user without the inverter desires energy saving. According to the present invention, it is noted that capacity control by an inverter consumes less electric power than the constant speed of a motor. An investment for the installation of the inverter is obtained by a reduced electric bill due to electric power saving as a service charge.
In the services disclosed in the patent documents 8 and 9, a user who has already installed the inverter cannot get the electric power saving effect. Thus, a service, which is described in the present invention, is not applicable thereto.
As described above, the methods for identifying the motor constants of the permanent magnet motor has begun to be proposed, but technology for using the results of identification has not yet put to practical use. Furthermore, a service for providing energy saving for the user, who has already installed an inverter, is difficult because of the foregoing reasons.
To solve the foregoing problems, an object of the present invention is to provide a service using a motor device with high reliability, which can always operate with high efficiency irrespective of position sensor drive control and position sensor-less drive control, and a service using a driving method of the motor. Another object is to provide a service which enables an exchange of a motor or a compressor with the motor even if motor constants of the motor are unknown, irrespective of position sensor drive control and position sensor-less drive control.
Further, another object is to obtain a service using a motor device and a driving method of a motor. In the motor device and the driving method of the motor, even if motor constants of the motor are unknown, the motor is operated in an efficient operating state while detecting the motor constants which vary every moment by operating the motor. Further another object of the invention is to obtain a service using a motor device and a driving method of a motor. In the motor device and the driving method of the motor, even if an inverter has been already installed, an exchange of a motor or a compressor for the motor with unknown motor constants is possible irrespective of position sensor drive control and position sensor-less drive control. The motor is operated in an efficient operating state.
Further, another object is to provide a service using a motor device, wherein position sensor-less drive is realized, and the motor device is efficiently operated by the position sensor-less drive. Further another object of the invention is to provide a service and a freezing/air conditioning device using a refrigeration cycle device with high efficiency and reliability.
Further another object of the present invention is to provide a service using a driving device of a motor. In the service, the motor has an estimator which can estimate the actual rotating coordinate axis of the motor, so as to realize the detection of a counter-electromotive voltage constant in any position sensor-less drive, and also realize the position sensor-less drive using the axis estimator. Further another object is to obtain a service using a driving device of a motor, which measures inductance with high precision irrespective of time of pulse application.
Further, another object of the present invention is to provide various types of service using a driving device of a motor. In the service, the driving device itself being an inverter converges an amount of applied voltage, an accelerated frequency, and a frequency for judging actuation to appropriate values in accordance with an axial load of a motor at starting, even if the motor has different specifications, in order to realize a positive startup of the motor and judge a starting state.
Further, another object of the present invention is to carrying out an exchange service to exchange a motor or a compressor for an efficient one, and an energy saving providing service. In the exchange service and the energy saving providing service, a driving device of the motor having the function of identifying motor constants is used. The function is structured so as to identify the motor constants which are necessary for driving the motor.
Further, another object is to provide an energy saving service which makes it possible for a customer to reduce initial investment cost for the change of facilities, and to achieve energy saving. Further another object is to provide a service using a driving device of a motor or the motor in which if the motor with any specifications is installed in a product, it is possible to develop the product in a short period and at low cost.